Hydraulic multistage control slide valve

ABSTRACT

A hydraulic spool-type control valve has a slide shiftable in opposite directions to connect hydraulic devices with a source of fluid, and a drive for the slide including a pair of levers bearing on opposite ends of the slide in opposing directions and controlled by respective cams synchronously driven by a controlled-flow hydraulic motor.

United States Patent Nowak et al.

[ Feb. 29,1972

HYDRAULIC MULTISTAGE CONTROL SLIDE VALVE Inventors: Edmund Nowak; JerzyKorchow, both of Warsaw, Poland Assignee: Zaklad Doswiadczalny PrasAutomatycznych Hydomat pny zakladach Mechanicznych Tarnow, Warsaw.Poland Filed: Apr. 8, 1970 Appl. No.: 26,647

Foreign Application Priority Data Apr. 28, I969 Poland ..P. 1 33,255

US. Cl ..l37/624.13, l37/625.69, I37/625.66,

251/229 Int. Cl ..Fl6k 11/02 Field of Search ..137/624.18, 624.13,624.15,

[56] References Cited FOREIGN PATENTS OR APPLICATIONS 496,529 7/1954Italy 1 37/624. I 7 356,506 2/I938 Italy l 37/624.7

Primary ExaminerAlan Cohan Attorney-Karl F. Ross [57] ABSTRACT Ahydraulic spool-type control valve has a slide shifiablc in oppositedirections to connect hydraulic devices with a source of fluid, and adrive for the slide including a pair of levers bearing on opposite endsof the slide in opposing directions and controlled by respective camssynchronously driven by a controlled-flow hydraulic motor.

5 Claims, 3 Drawing Figures PATENTEDFEB29 I972 3,645,295 SHEET 1 [IF 3Edmund Nawak Jerzy Korchow INV ENTORS.

BY 0 g, 1

ATTORNEY PATENTEDFEB29 m2 SHEET 2 BF 3 Edmund Nowak Jerzy KorchowINVENTORs.

ATTORNEY Pmminrcaze me 3,645,295

SHEET 3 OF 3 Fig.3

Edmund Nowak Jerzy Korchow INVENTORS.

ATTORNEY HYDRAULIC MULTISTAGE CONTROL SLIDE VALVE FIELD OF THE INVENTIONThis invention relates to a hydraulic multiple-stage control slide valveprovided with a ram-drive unit, composed of two alternately, actingpressure levers on opposite sides of the ram, controlled by means of oneor more coupled shafts provided with adjustable cam rings.

BACKGROUND OF THE INVENTION For hydraulic control of machines, hydrauliccontrol slide valves or spool valves are employed. Among the types ofsuch hydraulic control slide valves which enable a synchronized controlof units being driven by boosters or servomotors, there are hydraulicmultistage control slide valves.

The main unit of such a hydraulic control slide valve is the ram orplunger which is shifted in a reciprocating manner in the cylinder thusopening and closing the appropriate flow conduits.

For driving the hydraulic control slide valves known to date areelectric systems consisting of electromagnets switched on by means ofcurrent pulses emitted by an appropriate electric distributor or a limitswitch and causing the ram to reciprocate.

The main drawback of control slide valves of this kind is poorreliability of operation of the coupling of the electric system with thehydraulic system, the system being limited to a switching rate notexceeding three to five thousand switch operations per hour and therelatively high costs connected with the installation of complexelectric appliances.

There are also known multistage hydraulic control slide valves with aunit having an electric motor which drives by means of a gear the camthat moves the ram; the return movement of the ram is effected by theaction of a previously compressed spring.

The disadvantage of control slide valves of this latter type is the lackof reliability of operation, since in a case of jamming of the ram,e.g., due to impurities in the oil, the force of the restoring spring istoo small to overcome the resistance to the ram movement.

Besides, the force exerted on the ram in its movement overcoming theresistance of the spring must be, by many times, greater than the forceof the travel of the ram.

There are also known control slide valves whose rams are shifted bymeans of small hydraulic or pneumatic servomotors controlled,consequently, by means of electric distributors and having, in thisconnection, all the drawbacks connected with the application of electricsystems.

OBJECT OF THE INVENTION The object of this invention is the eliminationof the abovementioned disadvantages and the provision of a multistagehydraulic control valve, which is distinguished by a high reliability ofoperation and, at the same time, by a relatively simple and compactdesign and the easy setting up and changing of the working cyclecontrolled by the hydraulic control slide valve.

SUMMARY OF THE INVENTION This task has been solved, according to theinvention by providing a drive unit for the hydraulic control slidevalve with a system of two pressure levers alternately acting on bothsides of the valve rarn spool or plunger, controlled by one or moremutually coupled shafts having adjustable cam rings being clamped onthem.

For driving the shaft or coupled shafts preferably should be employed ahydraulic or hydraulic-mechanical system, for instance a hydraulic motorwith a governor for the flow speed of fluid, enabling a stepless changeof rotational speed of the shaft or shafts.

Owing to this, in the hydraulic control slide valve, according to theinvention, it is possible to completely eliminate the electric controland drive systems, and thus remove all drawbacks connected with it, andto increase the reliability of operation of the device.

Besides, the system of two alternately operating levers, of which oneshifts the ram in one direction while the other shifts the ram in theopposite direction, removes the disadvantages of control slide valvesprovided with return springs.

The multistage control slide valve, according to the invention, ischaracterized by a simple design and, moreover, enables setting up 'ofany control program of the working process being regulated by the ram.

Such a setting up consists, namely, in an appropriate adjustment of thecam rings on the shaft or coupled shafts, which enables any arrangementof the beginning and the termination of the working cycle to beestablished.

DESCRIPTION OF THE DRAWING The invention is explained by way of examplein the drawing, in which:

FIG. 1 shows the hydraulic control slide valve according to theinvention in a section along the axis of the ram;

FIG. 2 shows a drive having coupled shafts; and

FIG. 3 the multistage hydraulic control slide valve in a section alongthe axis of one of the coupled shafts.

SPECIFIC DESCRIPTION The hydraulic control slide valve, according to theinvention, consists of a cylinder 1 provided with a set of ports orconduits 2 connected to a feed conduit or port 3 and to outflow conduitsor ports 4 and of the ram, spool or plunger 5 slidably mounted insidethis cylinder 1, provided with connecting chambers 6.

The slide or ram 5 is shifted in appropriate moments of the workingcycle in a reciprocating way, thus establishing a connection ofappropriate ports 2, 4 by means of chambers 6.

For shifting the ram a mechanism is used consisting of two pressurelevers 7 and 8, rotatably mounted on the axles or fulcrum shafts 9 and10 or on one shaft, which levers act in an alternating way on the ram onits both opposite ends or sides,

For controlling these levers one, a single shaft or two mutually coupledshafts 11 and 12 are employed, driven within rotary movement withcontrollable, preferably stepless turning speed and provided with rings13 with earns 14 clamped on these shafts.

The cams 14 cooperate preferably with disks 15 (cam-follower rollers)rotatably mounted on ends of the levers 7 and 8, which are provided ontheir other ends with similar rotatably mounted disks or rollers 16cooperating with end surfaces of the ram 5.

For driving the shaft or coupled shafts l1 and 12, we may use in theexemplary design shown in FIG. 2, a mechanism consisting of a hydraulicmotor 17, with a speed governor for the liquid flow 18 which enables astepless change of turning speed of the motor; the worm 19 mounted onthe shaft of the motor 17 meshes with a worm wheel 20 carrying a gear21,22, whose wheel 21 is keyed on the shaft 1 l, and the wheel 22 on theshaft 12 coupled with the latter.

The multistage control slide valve as illustrated by way of example inFIG. 3 consists of a set of six cylinders la, lb, 1c, 1d, le, If withappropriate rams (not shown) which are moved in a reciprocating way bymeans of a set of levers 7a, 7b, 7c and oppositely acting levers (notshown).

For controlling these levers are used clamping rings 13a, 13b, with cams14a, 14b, mounted on shafts 11 and 12, only the former beingillustrated.

The operation of the hydraulic multistage control slide valve, describedabove by way of example, is as follows.

In order to set up a controlled program of the working cycle, we should,according to the timing of to the initial and final moment of the cycleof particular elements (loads) controlled by means of cylinders 1a,1b,...lf, set the rings 13 with cams 14 on the shaft or coupled shafts(cam shafts) 11 and 12 so, that the levers 71, 7b...7f etc., controlledby these cams involve a properly synchronized reciprocating movement ofthe rams 5.

The setting up of the proper length of the working cycle is obtained byproper regulation of the liquid flow through the hydraulic motor 17 bymeans of the speed governor 18.

After setting in motion the control slide valve, the levers 71, 7b...7fetc., controlled by cams 14a, l4b...l4f cause the appropriatelysynchronized shifting of rams in the cylinders la, lb... if. and thus,the controlling of wgrkigg elements, according to the required program.The holding of the ram in a reversed position is obtained by a pressuregenerated in the flow chamber.

Owing to the absence of electric units there has been obtained not onlya high reliability of operation of the control slide valve, according tothe invention, but also a considerable increase of the number of cyclesper time unit, e.g., to 60 thousand cycles per hour.

Besides, the control slide valve, according to the invention, ischaracterized by a simple and compact design and, thus, smalldimensions. It can be employed particularly in controlling hydraulicunits of various machines and technical installations.

What we claim is:

l. A hydraulic control valve, comprising a valve housing formed with acylinder having ports connectable in hydraulic circuit; a linearlyaxially shiftable elongated slide receivable in said cylinder andshiftable in opposite directions to control the flow of fluid in saidhydraulic circuit; respective levers pivotal about mutually parallelaxes transverse to said slide and engageable with one extremity of eachlever against a respective end of said slide; shaft means including atleast one shaft journaled in said housing; and respective cams mountedon said shaft means and angularly adjustable relative thereto and actingupon other extremities of the respective levers for displac- 3. Thevalve defined in claim 1, further comprising a hydraulic motoroperatively connected to said shaft means for driving same; and fluidflow rate control means maintaining an adjustable constant rate of flowof fluid thi'o u gh said motor.

4. The valve defined in claim 1 wherein said slide is so constructed andarranged that it is held in position by fluid pres sure within saidcylinder in the absence of a force applied thereto by one of saidlevers.

S. The valve defined in claim 1 wherein each of said levers is journaledon a respective fulcrum shaft intermediate its extremities, said fulcrumshafts being mutually parallel and parallel to said shaft means, each ofsaid levers being provided at its one extremity with a roller bearingupon a respective end of said slide and at its other extremity with acam-follower roller, said shaft means comprises a pair of mutuallyparallel transversely spaced cam shafts parallel to said fulcrum shafts,said cams each include a respective ring surrounded and adapted to betightened against the respective cam shaft, each of said rings beingprovided with a projection adapted to displace the respective camfollower roller, and said valve further comprising a gear transmissionoperatively connecting said cam shafts for synchronous rotation, a wormdrivingly connected with said gear transmission, a hydraulic motorconnected to said worm for rotating same, and adjustable flow controlmeans connected to said motor for setting a selected rate of operationthereof.

1. A hydraulic control valve, comprising a valve housing formed with acylinder having ports connectable in hydraulic circuit; a linearlyaxially shiftable elongated slide receivable in said cylinder andshiftable in opposite directions to control the flow of fluid in saidhydraulic circuit; respective levers pivotal about mutually parallelaxes transverse to said slide and engageable with one extremity of eachlever against a respective end of said slide; shaft means including atleast one shaft journaled in said housing; and respective cams mountedon said shaft means and angularly adjustable relative thereto and actingupon other extremities of the respective levers for displacing same toshift said slide in alternately opposite directions, said cams beingsynchronized with one another.
 2. The valve defined in claim 1 whereinsaid shaft means includes a respective shaft assigned to each of saidlevers and the respective cam associated with each lever is mounted onone of said shafts, said valve further comprising transmission meanscoupling said shafts for synchronous rotation.
 3. The valve defined inclaim 1, further comprising a hydraulic motor operatively connected tosaid shaft means for driving same; and fluid flow rate control meansmaintaining an adjustable constant rate of flow of fluid through saidmotor.
 4. The valve defined in claim 1 wherein said slide is soconstructed and arranged that it is held in position by fluid pressurewithin said cylinder in the absence of a force applied thereto by one ofsaid levers.
 5. The valve defined in claim 1 wherein each of said leversis journaled on a respective fulcrum shaft intermediate its extremities,said fulcrum shafts being mutually parallel and parallel to said shaftmeans, each of said levers being provided at its one extremity with aroller bearing upon a respective end of said slide and at its otherextremity with a cam-follower roller, said shaft means comprises a pairof mutually parallel transversely spaced cam shafts parallel to saidfulcrum shafts, said cams each include a respective ring surrounded andadapted to be tightened against the respective cam shaft, each of saidrings being provided with a projection adapted to displace thereSpective cam follower roller, and said valve further comprising a geartransmission operatively connecting said cam shafts for synchronousrotation, a worm drivingly connected with said gear transmission, ahydraulic motor connected to said worm for rotating same, and adjustableflow-control means connected to said motor for setting a selected rateof operation thereof.